The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_linker.c

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    1 /*-
    2  * Copyright (c) 1997-2000 Doug Rabson
    3  * All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  *
   14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   24  * SUCH DAMAGE.
   25  */
   26 
   27 #include <sys/cdefs.h>
   28 __FBSDID("$FreeBSD: stable/10/sys/kern/kern_linker.c 325867 2017-11-15 22:35:16Z gordon $");
   29 
   30 #include "opt_ddb.h"
   31 #include "opt_kld.h"
   32 #include "opt_hwpmc_hooks.h"
   33 
   34 #include <sys/param.h>
   35 #include <sys/kernel.h>
   36 #include <sys/systm.h>
   37 #include <sys/malloc.h>
   38 #include <sys/sysproto.h>
   39 #include <sys/sysent.h>
   40 #include <sys/priv.h>
   41 #include <sys/proc.h>
   42 #include <sys/lock.h>
   43 #include <sys/mutex.h>
   44 #include <sys/sx.h>
   45 #include <sys/module.h>
   46 #include <sys/mount.h>
   47 #include <sys/linker.h>
   48 #include <sys/eventhandler.h>
   49 #include <sys/fcntl.h>
   50 #include <sys/jail.h>
   51 #include <sys/libkern.h>
   52 #include <sys/namei.h>
   53 #include <sys/vnode.h>
   54 #include <sys/syscallsubr.h>
   55 #include <sys/sysctl.h>
   56 
   57 #include <net/vnet.h>
   58 
   59 #include <security/mac/mac_framework.h>
   60 
   61 #include "linker_if.h"
   62 
   63 #ifdef HWPMC_HOOKS
   64 #include <sys/pmckern.h>
   65 #endif
   66 
   67 #ifdef KLD_DEBUG
   68 int kld_debug = 0;
   69 SYSCTL_INT(_debug, OID_AUTO, kld_debug, CTLFLAG_RW | CTLFLAG_TUN,
   70     &kld_debug, 0, "Set various levels of KLD debug");
   71 TUNABLE_INT("debug.kld_debug", &kld_debug);
   72 #endif
   73 
   74 /* These variables are used by kernel debuggers to enumerate loaded files. */
   75 const int kld_off_address = offsetof(struct linker_file, address);
   76 const int kld_off_filename = offsetof(struct linker_file, filename);
   77 const int kld_off_pathname = offsetof(struct linker_file, pathname);
   78 const int kld_off_next = offsetof(struct linker_file, link.tqe_next);
   79 
   80 /*
   81  * static char *linker_search_path(const char *name, struct mod_depend
   82  * *verinfo);
   83  */
   84 static const char       *linker_basename(const char *path);
   85 
   86 /*
   87  * Find a currently loaded file given its filename.
   88  */
   89 static linker_file_t linker_find_file_by_name(const char* _filename);
   90 
   91 /*
   92  * Find a currently loaded file given its file id.
   93  */
   94 static linker_file_t linker_find_file_by_id(int _fileid);
   95 
   96 /* Metadata from the static kernel */
   97 SET_DECLARE(modmetadata_set, struct mod_metadata);
   98 
   99 MALLOC_DEFINE(M_LINKER, "linker", "kernel linker");
  100 
  101 linker_file_t linker_kernel_file;
  102 
  103 static struct sx kld_sx;        /* kernel linker lock */
  104 
  105 /*
  106  * Load counter used by clients to determine if a linker file has been
  107  * re-loaded. This counter is incremented for each file load.
  108  */
  109 static int loadcnt;
  110 
  111 static linker_class_list_t classes;
  112 static linker_file_list_t linker_files;
  113 static int next_file_id = 1;
  114 static int linker_no_more_classes = 0;
  115 
  116 #define LINKER_GET_NEXT_FILE_ID(a) do {                                 \
  117         linker_file_t lftmp;                                            \
  118                                                                         \
  119         if (!cold)                                                      \
  120                 sx_assert(&kld_sx, SA_XLOCKED);                         \
  121 retry:                                                                  \
  122         TAILQ_FOREACH(lftmp, &linker_files, link) {                     \
  123                 if (next_file_id == lftmp->id) {                        \
  124                         next_file_id++;                                 \
  125                         goto retry;                                     \
  126                 }                                                       \
  127         }                                                               \
  128         (a) = next_file_id;                                             \
  129 } while(0)
  130 
  131 
  132 /* XXX wrong name; we're looking at version provision tags here, not modules */
  133 typedef TAILQ_HEAD(, modlist) modlisthead_t;
  134 struct modlist {
  135         TAILQ_ENTRY(modlist) link;      /* chain together all modules */
  136         linker_file_t   container;
  137         const char      *name;
  138         int             version;
  139 };
  140 typedef struct modlist *modlist_t;
  141 static modlisthead_t found_modules;
  142 
  143 static int      linker_file_add_dependency(linker_file_t file,
  144                     linker_file_t dep);
  145 static caddr_t  linker_file_lookup_symbol_internal(linker_file_t file,
  146                     const char* name, int deps);
  147 static int      linker_load_module(const char *kldname,
  148                     const char *modname, struct linker_file *parent,
  149                     struct mod_depend *verinfo, struct linker_file **lfpp);
  150 static modlist_t modlist_lookup2(const char *name, struct mod_depend *verinfo);
  151 
  152 static void
  153 linker_init(void *arg)
  154 {
  155 
  156         sx_init(&kld_sx, "kernel linker");
  157         TAILQ_INIT(&classes);
  158         TAILQ_INIT(&linker_files);
  159 }
  160 
  161 SYSINIT(linker, SI_SUB_KLD, SI_ORDER_FIRST, linker_init, 0);
  162 
  163 static void
  164 linker_stop_class_add(void *arg)
  165 {
  166 
  167         linker_no_more_classes = 1;
  168 }
  169 
  170 SYSINIT(linker_class, SI_SUB_KLD, SI_ORDER_ANY, linker_stop_class_add, NULL);
  171 
  172 int
  173 linker_add_class(linker_class_t lc)
  174 {
  175 
  176         /*
  177          * We disallow any class registration past SI_ORDER_ANY
  178          * of SI_SUB_KLD.  We bump the reference count to keep the
  179          * ops from being freed.
  180          */
  181         if (linker_no_more_classes == 1)
  182                 return (EPERM);
  183         kobj_class_compile((kobj_class_t) lc);
  184         ((kobj_class_t)lc)->refs++;     /* XXX: kobj_mtx */
  185         TAILQ_INSERT_TAIL(&classes, lc, link);
  186         return (0);
  187 }
  188 
  189 static void
  190 linker_file_sysinit(linker_file_t lf)
  191 {
  192         struct sysinit **start, **stop, **sipp, **xipp, *save;
  193 
  194         KLD_DPF(FILE, ("linker_file_sysinit: calling SYSINITs for %s\n",
  195             lf->filename));
  196 
  197         sx_assert(&kld_sx, SA_XLOCKED);
  198 
  199         if (linker_file_lookup_set(lf, "sysinit_set", &start, &stop, NULL) != 0)
  200                 return;
  201         /*
  202          * Perform a bubble sort of the system initialization objects by
  203          * their subsystem (primary key) and order (secondary key).
  204          *
  205          * Since some things care about execution order, this is the operation
  206          * which ensures continued function.
  207          */
  208         for (sipp = start; sipp < stop; sipp++) {
  209                 for (xipp = sipp + 1; xipp < stop; xipp++) {
  210                         if ((*sipp)->subsystem < (*xipp)->subsystem ||
  211                             ((*sipp)->subsystem == (*xipp)->subsystem &&
  212                             (*sipp)->order <= (*xipp)->order))
  213                                 continue;       /* skip */
  214                         save = *sipp;
  215                         *sipp = *xipp;
  216                         *xipp = save;
  217                 }
  218         }
  219 
  220         /*
  221          * Traverse the (now) ordered list of system initialization tasks.
  222          * Perform each task, and continue on to the next task.
  223          */
  224         sx_xunlock(&kld_sx);
  225         mtx_lock(&Giant);
  226         for (sipp = start; sipp < stop; sipp++) {
  227                 if ((*sipp)->subsystem == SI_SUB_DUMMY)
  228                         continue;       /* skip dummy task(s) */
  229 
  230                 /* Call function */
  231                 (*((*sipp)->func)) ((*sipp)->udata);
  232         }
  233         mtx_unlock(&Giant);
  234         sx_xlock(&kld_sx);
  235 }
  236 
  237 static void
  238 linker_file_sysuninit(linker_file_t lf)
  239 {
  240         struct sysinit **start, **stop, **sipp, **xipp, *save;
  241 
  242         KLD_DPF(FILE, ("linker_file_sysuninit: calling SYSUNINITs for %s\n",
  243             lf->filename));
  244 
  245         sx_assert(&kld_sx, SA_XLOCKED);
  246 
  247         if (linker_file_lookup_set(lf, "sysuninit_set", &start, &stop,
  248             NULL) != 0)
  249                 return;
  250 
  251         /*
  252          * Perform a reverse bubble sort of the system initialization objects
  253          * by their subsystem (primary key) and order (secondary key).
  254          *
  255          * Since some things care about execution order, this is the operation
  256          * which ensures continued function.
  257          */
  258         for (sipp = start; sipp < stop; sipp++) {
  259                 for (xipp = sipp + 1; xipp < stop; xipp++) {
  260                         if ((*sipp)->subsystem > (*xipp)->subsystem ||
  261                             ((*sipp)->subsystem == (*xipp)->subsystem &&
  262                             (*sipp)->order >= (*xipp)->order))
  263                                 continue;       /* skip */
  264                         save = *sipp;
  265                         *sipp = *xipp;
  266                         *xipp = save;
  267                 }
  268         }
  269 
  270         /*
  271          * Traverse the (now) ordered list of system initialization tasks.
  272          * Perform each task, and continue on to the next task.
  273          */
  274         sx_xunlock(&kld_sx);
  275         mtx_lock(&Giant);
  276         for (sipp = start; sipp < stop; sipp++) {
  277                 if ((*sipp)->subsystem == SI_SUB_DUMMY)
  278                         continue;       /* skip dummy task(s) */
  279 
  280                 /* Call function */
  281                 (*((*sipp)->func)) ((*sipp)->udata);
  282         }
  283         mtx_unlock(&Giant);
  284         sx_xlock(&kld_sx);
  285 }
  286 
  287 static void
  288 linker_file_register_sysctls(linker_file_t lf, bool enable)
  289 {
  290         struct sysctl_oid **start, **stop, **oidp;
  291 
  292         KLD_DPF(FILE,
  293             ("linker_file_register_sysctls: registering SYSCTLs for %s\n",
  294             lf->filename));
  295 
  296         sx_assert(&kld_sx, SA_XLOCKED);
  297 
  298         if (linker_file_lookup_set(lf, "sysctl_set", &start, &stop, NULL) != 0)
  299                 return;
  300 
  301         sx_xunlock(&kld_sx);
  302         sysctl_lock();
  303         for (oidp = start; oidp < stop; oidp++) {
  304                 if (enable)
  305                         sysctl_register_oid(*oidp);
  306                 else
  307                         sysctl_register_disabled_oid(*oidp);
  308         }
  309         sysctl_unlock();
  310         sx_xlock(&kld_sx);
  311 }
  312 
  313 static void
  314 linker_file_enable_sysctls(linker_file_t lf)
  315 {
  316         struct sysctl_oid **start, **stop, **oidp;
  317 
  318         KLD_DPF(FILE,
  319             ("linker_file_enable_sysctls: enable SYSCTLs for %s\n",
  320             lf->filename));
  321 
  322         sx_assert(&kld_sx, SA_XLOCKED);
  323 
  324         if (linker_file_lookup_set(lf, "sysctl_set", &start, &stop, NULL) != 0)
  325                 return;
  326 
  327         sx_xunlock(&kld_sx);
  328         sysctl_lock();
  329         for (oidp = start; oidp < stop; oidp++)
  330                 sysctl_enable_oid(*oidp);
  331         sysctl_unlock();
  332         sx_xlock(&kld_sx);
  333 }
  334 
  335 static void
  336 linker_file_unregister_sysctls(linker_file_t lf)
  337 {
  338         struct sysctl_oid **start, **stop, **oidp;
  339 
  340         KLD_DPF(FILE, ("linker_file_unregister_sysctls: unregistering SYSCTLs"
  341             " for %s\n", lf->filename));
  342 
  343         sx_assert(&kld_sx, SA_XLOCKED);
  344 
  345         if (linker_file_lookup_set(lf, "sysctl_set", &start, &stop, NULL) != 0)
  346                 return;
  347 
  348         sx_xunlock(&kld_sx);
  349         sysctl_lock();
  350         for (oidp = start; oidp < stop; oidp++)
  351                 sysctl_unregister_oid(*oidp);
  352         sysctl_unlock();
  353         sx_xlock(&kld_sx);
  354 }
  355 
  356 static int
  357 linker_file_register_modules(linker_file_t lf)
  358 {
  359         struct mod_metadata **start, **stop, **mdp;
  360         const moduledata_t *moddata;
  361         int first_error, error;
  362 
  363         KLD_DPF(FILE, ("linker_file_register_modules: registering modules"
  364             " in %s\n", lf->filename));
  365 
  366         sx_assert(&kld_sx, SA_XLOCKED);
  367 
  368         if (linker_file_lookup_set(lf, "modmetadata_set", &start,
  369             &stop, NULL) != 0) {
  370                 /*
  371                  * This fallback should be unnecessary, but if we get booted
  372                  * from boot2 instead of loader and we are missing our
  373                  * metadata then we have to try the best we can.
  374                  */
  375                 if (lf == linker_kernel_file) {
  376                         start = SET_BEGIN(modmetadata_set);
  377                         stop = SET_LIMIT(modmetadata_set);
  378                 } else
  379                         return (0);
  380         }
  381         first_error = 0;
  382         for (mdp = start; mdp < stop; mdp++) {
  383                 if ((*mdp)->md_type != MDT_MODULE)
  384                         continue;
  385                 moddata = (*mdp)->md_data;
  386                 KLD_DPF(FILE, ("Registering module %s in %s\n",
  387                     moddata->name, lf->filename));
  388                 error = module_register(moddata, lf);
  389                 if (error) {
  390                         printf("Module %s failed to register: %d\n",
  391                             moddata->name, error);
  392                         if (first_error == 0)
  393                                 first_error = error;
  394                 }
  395         }
  396         return (first_error);
  397 }
  398 
  399 static void
  400 linker_init_kernel_modules(void)
  401 {
  402 
  403         sx_xlock(&kld_sx);
  404         linker_file_register_modules(linker_kernel_file);
  405         sx_xunlock(&kld_sx);
  406 }
  407 
  408 SYSINIT(linker_kernel, SI_SUB_KLD, SI_ORDER_ANY, linker_init_kernel_modules,
  409     0);
  410 
  411 static int
  412 linker_load_file(const char *filename, linker_file_t *result)
  413 {
  414         linker_class_t lc;
  415         linker_file_t lf;
  416         int foundfile, error, modules;
  417 
  418         /* Refuse to load modules if securelevel raised */
  419         if (prison0.pr_securelevel > 0)
  420                 return (EPERM);
  421 
  422         sx_assert(&kld_sx, SA_XLOCKED);
  423         lf = linker_find_file_by_name(filename);
  424         if (lf) {
  425                 KLD_DPF(FILE, ("linker_load_file: file %s is already loaded,"
  426                     " incrementing refs\n", filename));
  427                 *result = lf;
  428                 lf->refs++;
  429                 return (0);
  430         }
  431         foundfile = 0;
  432         error = 0;
  433 
  434         /*
  435          * We do not need to protect (lock) classes here because there is
  436          * no class registration past startup (SI_SUB_KLD, SI_ORDER_ANY)
  437          * and there is no class deregistration mechanism at this time.
  438          */
  439         TAILQ_FOREACH(lc, &classes, link) {
  440                 KLD_DPF(FILE, ("linker_load_file: trying to load %s\n",
  441                     filename));
  442                 error = LINKER_LOAD_FILE(lc, filename, &lf);
  443                 /*
  444                  * If we got something other than ENOENT, then it exists but
  445                  * we cannot load it for some other reason.
  446                  */
  447                 if (error != ENOENT)
  448                         foundfile = 1;
  449                 if (lf) {
  450                         error = linker_file_register_modules(lf);
  451                         if (error == EEXIST) {
  452                                 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
  453                                 return (error);
  454                         }
  455                         modules = !TAILQ_EMPTY(&lf->modules);
  456                         linker_file_register_sysctls(lf, false);
  457                         linker_file_sysinit(lf);
  458                         lf->flags |= LINKER_FILE_LINKED;
  459 
  460                         /*
  461                          * If all of the modules in this file failed
  462                          * to load, unload the file and return an
  463                          * error of ENOEXEC.
  464                          */
  465                         if (modules && TAILQ_EMPTY(&lf->modules)) {
  466                                 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
  467                                 return (ENOEXEC);
  468                         }
  469                         linker_file_enable_sysctls(lf);
  470                         EVENTHANDLER_INVOKE(kld_load, lf);
  471                         *result = lf;
  472                         return (0);
  473                 }
  474         }
  475         /*
  476          * Less than ideal, but tells the user whether it failed to load or
  477          * the module was not found.
  478          */
  479         if (foundfile) {
  480 
  481                 /*
  482                  * If the file type has not been recognized by the last try
  483                  * printout a message before to fail.
  484                  */
  485                 if (error == ENOSYS)
  486                         printf("linker_load_file: Unsupported file type\n");
  487 
  488                 /*
  489                  * Format not recognized or otherwise unloadable.
  490                  * When loading a module that is statically built into
  491                  * the kernel EEXIST percolates back up as the return
  492                  * value.  Preserve this so that apps like sysinstall
  493                  * can recognize this special case and not post bogus
  494                  * dialog boxes.
  495                  */
  496                 if (error != EEXIST)
  497                         error = ENOEXEC;
  498         } else
  499                 error = ENOENT;         /* Nothing found */
  500         return (error);
  501 }
  502 
  503 int
  504 linker_reference_module(const char *modname, struct mod_depend *verinfo,
  505     linker_file_t *result)
  506 {
  507         modlist_t mod;
  508         int error;
  509 
  510         sx_xlock(&kld_sx);
  511         if ((mod = modlist_lookup2(modname, verinfo)) != NULL) {
  512                 *result = mod->container;
  513                 (*result)->refs++;
  514                 sx_xunlock(&kld_sx);
  515                 return (0);
  516         }
  517 
  518         error = linker_load_module(NULL, modname, NULL, verinfo, result);
  519         sx_xunlock(&kld_sx);
  520         return (error);
  521 }
  522 
  523 int
  524 linker_release_module(const char *modname, struct mod_depend *verinfo,
  525     linker_file_t lf)
  526 {
  527         modlist_t mod;
  528         int error;
  529 
  530         sx_xlock(&kld_sx);
  531         if (lf == NULL) {
  532                 KASSERT(modname != NULL,
  533                     ("linker_release_module: no file or name"));
  534                 mod = modlist_lookup2(modname, verinfo);
  535                 if (mod == NULL) {
  536                         sx_xunlock(&kld_sx);
  537                         return (ESRCH);
  538                 }
  539                 lf = mod->container;
  540         } else
  541                 KASSERT(modname == NULL && verinfo == NULL,
  542                     ("linker_release_module: both file and name"));
  543         error = linker_file_unload(lf, LINKER_UNLOAD_NORMAL);
  544         sx_xunlock(&kld_sx);
  545         return (error);
  546 }
  547 
  548 static linker_file_t
  549 linker_find_file_by_name(const char *filename)
  550 {
  551         linker_file_t lf;
  552         char *koname;
  553 
  554         koname = malloc(strlen(filename) + 4, M_LINKER, M_WAITOK);
  555         sprintf(koname, "%s.ko", filename);
  556 
  557         sx_assert(&kld_sx, SA_XLOCKED);
  558         TAILQ_FOREACH(lf, &linker_files, link) {
  559                 if (strcmp(lf->filename, koname) == 0)
  560                         break;
  561                 if (strcmp(lf->filename, filename) == 0)
  562                         break;
  563         }
  564         free(koname, M_LINKER);
  565         return (lf);
  566 }
  567 
  568 static linker_file_t
  569 linker_find_file_by_id(int fileid)
  570 {
  571         linker_file_t lf;
  572 
  573         sx_assert(&kld_sx, SA_XLOCKED);
  574         TAILQ_FOREACH(lf, &linker_files, link)
  575                 if (lf->id == fileid && lf->flags & LINKER_FILE_LINKED)
  576                         break;
  577         return (lf);
  578 }
  579 
  580 int
  581 linker_file_foreach(linker_predicate_t *predicate, void *context)
  582 {
  583         linker_file_t lf;
  584         int retval = 0;
  585 
  586         sx_xlock(&kld_sx);
  587         TAILQ_FOREACH(lf, &linker_files, link) {
  588                 retval = predicate(lf, context);
  589                 if (retval != 0)
  590                         break;
  591         }
  592         sx_xunlock(&kld_sx);
  593         return (retval);
  594 }
  595 
  596 linker_file_t
  597 linker_make_file(const char *pathname, linker_class_t lc)
  598 {
  599         linker_file_t lf;
  600         const char *filename;
  601 
  602         if (!cold)
  603                 sx_assert(&kld_sx, SA_XLOCKED);
  604         filename = linker_basename(pathname);
  605 
  606         KLD_DPF(FILE, ("linker_make_file: new file, filename='%s' for pathname='%s'\n", filename, pathname));
  607         lf = (linker_file_t)kobj_create((kobj_class_t)lc, M_LINKER, M_WAITOK);
  608         if (lf == NULL)
  609                 return (NULL);
  610         lf->refs = 1;
  611         lf->userrefs = 0;
  612         lf->flags = 0;
  613         lf->filename = strdup(filename, M_LINKER);
  614         lf->pathname = strdup(pathname, M_LINKER);
  615         LINKER_GET_NEXT_FILE_ID(lf->id);
  616         lf->ndeps = 0;
  617         lf->deps = NULL;
  618         lf->loadcnt = ++loadcnt;
  619         STAILQ_INIT(&lf->common);
  620         TAILQ_INIT(&lf->modules);
  621         TAILQ_INSERT_TAIL(&linker_files, lf, link);
  622         return (lf);
  623 }
  624 
  625 int
  626 linker_file_unload(linker_file_t file, int flags)
  627 {
  628         module_t mod, next;
  629         modlist_t ml, nextml;
  630         struct common_symbol *cp;
  631         int error, i;
  632 
  633         /* Refuse to unload modules if securelevel raised. */
  634         if (prison0.pr_securelevel > 0)
  635                 return (EPERM);
  636 
  637         sx_assert(&kld_sx, SA_XLOCKED);
  638         KLD_DPF(FILE, ("linker_file_unload: lf->refs=%d\n", file->refs));
  639 
  640         /* Easy case of just dropping a reference. */
  641         if (file->refs > 1) {
  642                 file->refs--;
  643                 return (0);
  644         }
  645 
  646         /* Give eventhandlers a chance to prevent the unload. */
  647         error = 0;
  648         EVENTHANDLER_INVOKE(kld_unload_try, file, &error);
  649         if (error != 0)
  650                 return (EBUSY);
  651 
  652         KLD_DPF(FILE, ("linker_file_unload: file is unloading,"
  653             " informing modules\n"));
  654 
  655         /*
  656          * Quiesce all the modules to give them a chance to veto the unload.
  657          */
  658         MOD_SLOCK;
  659         for (mod = TAILQ_FIRST(&file->modules); mod;
  660              mod = module_getfnext(mod)) {
  661 
  662                 error = module_quiesce(mod);
  663                 if (error != 0 && flags != LINKER_UNLOAD_FORCE) {
  664                         KLD_DPF(FILE, ("linker_file_unload: module %s"
  665                             " vetoed unload\n", module_getname(mod)));
  666                         /*
  667                          * XXX: Do we need to tell all the quiesced modules
  668                          * that they can resume work now via a new module
  669                          * event?
  670                          */
  671                         MOD_SUNLOCK;
  672                         return (error);
  673                 }
  674         }
  675         MOD_SUNLOCK;
  676 
  677         /*
  678          * Inform any modules associated with this file that they are
  679          * being unloaded.
  680          */
  681         MOD_XLOCK;
  682         for (mod = TAILQ_FIRST(&file->modules); mod; mod = next) {
  683                 next = module_getfnext(mod);
  684                 MOD_XUNLOCK;
  685 
  686                 /*
  687                  * Give the module a chance to veto the unload.
  688                  */
  689                 if ((error = module_unload(mod)) != 0) {
  690 #ifdef KLD_DEBUG
  691                         MOD_SLOCK;
  692                         KLD_DPF(FILE, ("linker_file_unload: module %s"
  693                             " failed unload\n", module_getname(mod)));
  694                         MOD_SUNLOCK;
  695 #endif
  696                         return (error);
  697                 }
  698                 MOD_XLOCK;
  699                 module_release(mod);
  700         }
  701         MOD_XUNLOCK;
  702 
  703         TAILQ_FOREACH_SAFE(ml, &found_modules, link, nextml) {
  704                 if (ml->container == file) {
  705                         TAILQ_REMOVE(&found_modules, ml, link);
  706                         free(ml, M_LINKER);
  707                 }
  708         }
  709 
  710         /*
  711          * Don't try to run SYSUNINITs if we are unloaded due to a
  712          * link error.
  713          */
  714         if (file->flags & LINKER_FILE_LINKED) {
  715                 file->flags &= ~LINKER_FILE_LINKED;
  716                 linker_file_unregister_sysctls(file);
  717                 linker_file_sysuninit(file);
  718         }
  719         TAILQ_REMOVE(&linker_files, file, link);
  720 
  721         if (file->deps) {
  722                 for (i = 0; i < file->ndeps; i++)
  723                         linker_file_unload(file->deps[i], flags);
  724                 free(file->deps, M_LINKER);
  725                 file->deps = NULL;
  726         }
  727         while ((cp = STAILQ_FIRST(&file->common)) != NULL) {
  728                 STAILQ_REMOVE_HEAD(&file->common, link);
  729                 free(cp, M_LINKER);
  730         }
  731 
  732         LINKER_UNLOAD(file);
  733 
  734         EVENTHANDLER_INVOKE(kld_unload, file->filename, file->address,
  735             file->size);
  736 
  737         if (file->filename) {
  738                 free(file->filename, M_LINKER);
  739                 file->filename = NULL;
  740         }
  741         if (file->pathname) {
  742                 free(file->pathname, M_LINKER);
  743                 file->pathname = NULL;
  744         }
  745         kobj_delete((kobj_t) file, M_LINKER);
  746         return (0);
  747 }
  748 
  749 int
  750 linker_ctf_get(linker_file_t file, linker_ctf_t *lc)
  751 {
  752         return (LINKER_CTF_GET(file, lc));
  753 }
  754 
  755 static int
  756 linker_file_add_dependency(linker_file_t file, linker_file_t dep)
  757 {
  758         linker_file_t *newdeps;
  759 
  760         sx_assert(&kld_sx, SA_XLOCKED);
  761         file->deps = realloc(file->deps, (file->ndeps + 1) * sizeof(*newdeps),
  762             M_LINKER, M_WAITOK | M_ZERO);
  763         file->deps[file->ndeps] = dep;
  764         file->ndeps++;
  765         KLD_DPF(FILE, ("linker_file_add_dependency:"
  766             " adding %s as dependency for %s\n", 
  767             dep->filename, file->filename));
  768         return (0);
  769 }
  770 
  771 /*
  772  * Locate a linker set and its contents.  This is a helper function to avoid
  773  * linker_if.h exposure elsewhere.  Note: firstp and lastp are really void **.
  774  * This function is used in this file so we can avoid having lots of (void **)
  775  * casts.
  776  */
  777 int
  778 linker_file_lookup_set(linker_file_t file, const char *name,
  779     void *firstp, void *lastp, int *countp)
  780 {
  781 
  782         sx_assert(&kld_sx, SA_LOCKED);
  783         return (LINKER_LOOKUP_SET(file, name, firstp, lastp, countp));
  784 }
  785 
  786 /*
  787  * List all functions in a file.
  788  */
  789 int
  790 linker_file_function_listall(linker_file_t lf,
  791     linker_function_nameval_callback_t callback_func, void *arg)
  792 {
  793         return (LINKER_EACH_FUNCTION_NAMEVAL(lf, callback_func, arg));
  794 }
  795 
  796 caddr_t
  797 linker_file_lookup_symbol(linker_file_t file, const char *name, int deps)
  798 {
  799         caddr_t sym;
  800         int locked;
  801 
  802         locked = sx_xlocked(&kld_sx);
  803         if (!locked)
  804                 sx_xlock(&kld_sx);
  805         sym = linker_file_lookup_symbol_internal(file, name, deps);
  806         if (!locked)
  807                 sx_xunlock(&kld_sx);
  808         return (sym);
  809 }
  810 
  811 static caddr_t
  812 linker_file_lookup_symbol_internal(linker_file_t file, const char *name,
  813     int deps)
  814 {
  815         c_linker_sym_t sym;
  816         linker_symval_t symval;
  817         caddr_t address;
  818         size_t common_size = 0;
  819         int i;
  820 
  821         sx_assert(&kld_sx, SA_XLOCKED);
  822         KLD_DPF(SYM, ("linker_file_lookup_symbol: file=%p, name=%s, deps=%d\n",
  823             file, name, deps));
  824 
  825         if (LINKER_LOOKUP_SYMBOL(file, name, &sym) == 0) {
  826                 LINKER_SYMBOL_VALUES(file, sym, &symval);
  827                 if (symval.value == 0)
  828                         /*
  829                          * For commons, first look them up in the
  830                          * dependencies and only allocate space if not found
  831                          * there.
  832                          */
  833                         common_size = symval.size;
  834                 else {
  835                         KLD_DPF(SYM, ("linker_file_lookup_symbol: symbol"
  836                             ".value=%p\n", symval.value));
  837                         return (symval.value);
  838                 }
  839         }
  840         if (deps) {
  841                 for (i = 0; i < file->ndeps; i++) {
  842                         address = linker_file_lookup_symbol_internal(
  843                             file->deps[i], name, 0);
  844                         if (address) {
  845                                 KLD_DPF(SYM, ("linker_file_lookup_symbol:"
  846                                     " deps value=%p\n", address));
  847                                 return (address);
  848                         }
  849                 }
  850         }
  851         if (common_size > 0) {
  852                 /*
  853                  * This is a common symbol which was not found in the
  854                  * dependencies.  We maintain a simple common symbol table in
  855                  * the file object.
  856                  */
  857                 struct common_symbol *cp;
  858 
  859                 STAILQ_FOREACH(cp, &file->common, link) {
  860                         if (strcmp(cp->name, name) == 0) {
  861                                 KLD_DPF(SYM, ("linker_file_lookup_symbol:"
  862                                     " old common value=%p\n", cp->address));
  863                                 return (cp->address);
  864                         }
  865                 }
  866                 /*
  867                  * Round the symbol size up to align.
  868                  */
  869                 common_size = (common_size + sizeof(int) - 1) & -sizeof(int);
  870                 cp = malloc(sizeof(struct common_symbol)
  871                     + common_size + strlen(name) + 1, M_LINKER,
  872                     M_WAITOK | M_ZERO);
  873                 cp->address = (caddr_t)(cp + 1);
  874                 cp->name = cp->address + common_size;
  875                 strcpy(cp->name, name);
  876                 bzero(cp->address, common_size);
  877                 STAILQ_INSERT_TAIL(&file->common, cp, link);
  878 
  879                 KLD_DPF(SYM, ("linker_file_lookup_symbol: new common"
  880                     " value=%p\n", cp->address));
  881                 return (cp->address);
  882         }
  883         KLD_DPF(SYM, ("linker_file_lookup_symbol: fail\n"));
  884         return (0);
  885 }
  886 
  887 /*
  888  * Both DDB and stack(9) rely on the kernel linker to provide forward and
  889  * backward lookup of symbols.  However, DDB and sometimes stack(9) need to
  890  * do this in a lockfree manner.  We provide a set of internal helper
  891  * routines to perform these operations without locks, and then wrappers that
  892  * optionally lock.
  893  *
  894  * linker_debug_lookup() is ifdef DDB as currently it's only used by DDB.
  895  */
  896 #ifdef DDB
  897 static int
  898 linker_debug_lookup(const char *symstr, c_linker_sym_t *sym)
  899 {
  900         linker_file_t lf;
  901 
  902         TAILQ_FOREACH(lf, &linker_files, link) {
  903                 if (LINKER_LOOKUP_SYMBOL(lf, symstr, sym) == 0)
  904                         return (0);
  905         }
  906         return (ENOENT);
  907 }
  908 #endif
  909 
  910 static int
  911 linker_debug_search_symbol(caddr_t value, c_linker_sym_t *sym, long *diffp)
  912 {
  913         linker_file_t lf;
  914         c_linker_sym_t best, es;
  915         u_long diff, bestdiff, off;
  916 
  917         best = 0;
  918         off = (uintptr_t)value;
  919         bestdiff = off;
  920         TAILQ_FOREACH(lf, &linker_files, link) {
  921                 if (LINKER_SEARCH_SYMBOL(lf, value, &es, &diff) != 0)
  922                         continue;
  923                 if (es != 0 && diff < bestdiff) {
  924                         best = es;
  925                         bestdiff = diff;
  926                 }
  927                 if (bestdiff == 0)
  928                         break;
  929         }
  930         if (best) {
  931                 *sym = best;
  932                 *diffp = bestdiff;
  933                 return (0);
  934         } else {
  935                 *sym = 0;
  936                 *diffp = off;
  937                 return (ENOENT);
  938         }
  939 }
  940 
  941 static int
  942 linker_debug_symbol_values(c_linker_sym_t sym, linker_symval_t *symval)
  943 {
  944         linker_file_t lf;
  945 
  946         TAILQ_FOREACH(lf, &linker_files, link) {
  947                 if (LINKER_SYMBOL_VALUES(lf, sym, symval) == 0)
  948                         return (0);
  949         }
  950         return (ENOENT);
  951 }
  952 
  953 static int
  954 linker_debug_search_symbol_name(caddr_t value, char *buf, u_int buflen,
  955     long *offset)
  956 {
  957         linker_symval_t symval;
  958         c_linker_sym_t sym;
  959         int error;
  960 
  961         *offset = 0;
  962         error = linker_debug_search_symbol(value, &sym, offset);
  963         if (error)
  964                 return (error);
  965         error = linker_debug_symbol_values(sym, &symval);
  966         if (error)
  967                 return (error);
  968         strlcpy(buf, symval.name, buflen);
  969         return (0);
  970 }
  971 
  972 /*
  973  * DDB Helpers.  DDB has to look across multiple files with their own symbol
  974  * tables and string tables.
  975  *
  976  * Note that we do not obey list locking protocols here.  We really don't need
  977  * DDB to hang because somebody's got the lock held.  We'll take the chance
  978  * that the files list is inconsistent instead.
  979  */
  980 #ifdef DDB
  981 int
  982 linker_ddb_lookup(const char *symstr, c_linker_sym_t *sym)
  983 {
  984 
  985         return (linker_debug_lookup(symstr, sym));
  986 }
  987 #endif
  988 
  989 int
  990 linker_ddb_search_symbol(caddr_t value, c_linker_sym_t *sym, long *diffp)
  991 {
  992 
  993         return (linker_debug_search_symbol(value, sym, diffp));
  994 }
  995 
  996 int
  997 linker_ddb_symbol_values(c_linker_sym_t sym, linker_symval_t *symval)
  998 {
  999 
 1000         return (linker_debug_symbol_values(sym, symval));
 1001 }
 1002 
 1003 int
 1004 linker_ddb_search_symbol_name(caddr_t value, char *buf, u_int buflen,
 1005     long *offset)
 1006 {
 1007 
 1008         return (linker_debug_search_symbol_name(value, buf, buflen, offset));
 1009 }
 1010 
 1011 /*
 1012  * stack(9) helper for non-debugging environemnts.  Unlike DDB helpers, we do
 1013  * obey locking protocols, and offer a significantly less complex interface.
 1014  */
 1015 int
 1016 linker_search_symbol_name(caddr_t value, char *buf, u_int buflen,
 1017     long *offset)
 1018 {
 1019         int error;
 1020 
 1021         sx_xlock(&kld_sx);
 1022         error = linker_debug_search_symbol_name(value, buf, buflen, offset);
 1023         sx_xunlock(&kld_sx);
 1024         return (error);
 1025 }
 1026 
 1027 /*
 1028  * Syscalls.
 1029  */
 1030 int
 1031 kern_kldload(struct thread *td, const char *file, int *fileid)
 1032 {
 1033         const char *kldname, *modname;
 1034         linker_file_t lf;
 1035         int error;
 1036 
 1037         if ((error = securelevel_gt(td->td_ucred, 0)) != 0)
 1038                 return (error);
 1039 
 1040         if ((error = priv_check(td, PRIV_KLD_LOAD)) != 0)
 1041                 return (error);
 1042 
 1043         /*
 1044          * It is possible that kldloaded module will attach a new ifnet,
 1045          * so vnet context must be set when this ocurs.
 1046          */
 1047         CURVNET_SET(TD_TO_VNET(td));
 1048 
 1049         /*
 1050          * If file does not contain a qualified name or any dot in it
 1051          * (kldname.ko, or kldname.ver.ko) treat it as an interface
 1052          * name.
 1053          */
 1054         if (strchr(file, '/') || strchr(file, '.')) {
 1055                 kldname = file;
 1056                 modname = NULL;
 1057         } else {
 1058                 kldname = NULL;
 1059                 modname = file;
 1060         }
 1061 
 1062         sx_xlock(&kld_sx);
 1063         error = linker_load_module(kldname, modname, NULL, NULL, &lf);
 1064         if (error) {
 1065                 sx_xunlock(&kld_sx);
 1066                 goto done;
 1067         }
 1068         lf->userrefs++;
 1069         if (fileid != NULL)
 1070                 *fileid = lf->id;
 1071         sx_xunlock(&kld_sx);
 1072 
 1073 done:
 1074         CURVNET_RESTORE();
 1075         return (error);
 1076 }
 1077 
 1078 int
 1079 sys_kldload(struct thread *td, struct kldload_args *uap)
 1080 {
 1081         char *pathname = NULL;
 1082         int error, fileid;
 1083 
 1084         td->td_retval[0] = -1;
 1085 
 1086         pathname = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
 1087         error = copyinstr(uap->file, pathname, MAXPATHLEN, NULL);
 1088         if (error == 0) {
 1089                 error = kern_kldload(td, pathname, &fileid);
 1090                 if (error == 0)
 1091                         td->td_retval[0] = fileid;
 1092         }
 1093         free(pathname, M_TEMP);
 1094         return (error);
 1095 }
 1096 
 1097 int
 1098 kern_kldunload(struct thread *td, int fileid, int flags)
 1099 {
 1100         linker_file_t lf;
 1101         int error = 0;
 1102 
 1103         if ((error = securelevel_gt(td->td_ucred, 0)) != 0)
 1104                 return (error);
 1105 
 1106         if ((error = priv_check(td, PRIV_KLD_UNLOAD)) != 0)
 1107                 return (error);
 1108 
 1109         CURVNET_SET(TD_TO_VNET(td));
 1110         sx_xlock(&kld_sx);
 1111         lf = linker_find_file_by_id(fileid);
 1112         if (lf) {
 1113                 KLD_DPF(FILE, ("kldunload: lf->userrefs=%d\n", lf->userrefs));
 1114 
 1115                 if (lf->userrefs == 0) {
 1116                         /*
 1117                          * XXX: maybe LINKER_UNLOAD_FORCE should override ?
 1118                          */
 1119                         printf("kldunload: attempt to unload file that was"
 1120                             " loaded by the kernel\n");
 1121                         error = EBUSY;
 1122                 } else {
 1123                         lf->userrefs--;
 1124                         error = linker_file_unload(lf, flags);
 1125                         if (error)
 1126                                 lf->userrefs++;
 1127                 }
 1128         } else
 1129                 error = ENOENT;
 1130         sx_xunlock(&kld_sx);
 1131 
 1132         CURVNET_RESTORE();
 1133         return (error);
 1134 }
 1135 
 1136 int
 1137 sys_kldunload(struct thread *td, struct kldunload_args *uap)
 1138 {
 1139 
 1140         return (kern_kldunload(td, uap->fileid, LINKER_UNLOAD_NORMAL));
 1141 }
 1142 
 1143 int
 1144 sys_kldunloadf(struct thread *td, struct kldunloadf_args *uap)
 1145 {
 1146 
 1147         if (uap->flags != LINKER_UNLOAD_NORMAL &&
 1148             uap->flags != LINKER_UNLOAD_FORCE)
 1149                 return (EINVAL);
 1150         return (kern_kldunload(td, uap->fileid, uap->flags));
 1151 }
 1152 
 1153 int
 1154 sys_kldfind(struct thread *td, struct kldfind_args *uap)
 1155 {
 1156         char *pathname;
 1157         const char *filename;
 1158         linker_file_t lf;
 1159         int error;
 1160 
 1161 #ifdef MAC
 1162         error = mac_kld_check_stat(td->td_ucred);
 1163         if (error)
 1164                 return (error);
 1165 #endif
 1166 
 1167         td->td_retval[0] = -1;
 1168 
 1169         pathname = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
 1170         if ((error = copyinstr(uap->file, pathname, MAXPATHLEN, NULL)) != 0)
 1171                 goto out;
 1172 
 1173         filename = linker_basename(pathname);
 1174         sx_xlock(&kld_sx);
 1175         lf = linker_find_file_by_name(filename);
 1176         if (lf)
 1177                 td->td_retval[0] = lf->id;
 1178         else
 1179                 error = ENOENT;
 1180         sx_xunlock(&kld_sx);
 1181 out:
 1182         free(pathname, M_TEMP);
 1183         return (error);
 1184 }
 1185 
 1186 int
 1187 sys_kldnext(struct thread *td, struct kldnext_args *uap)
 1188 {
 1189         linker_file_t lf;
 1190         int error = 0;
 1191 
 1192 #ifdef MAC
 1193         error = mac_kld_check_stat(td->td_ucred);
 1194         if (error)
 1195                 return (error);
 1196 #endif
 1197 
 1198         sx_xlock(&kld_sx);
 1199         if (uap->fileid == 0)
 1200                 lf = TAILQ_FIRST(&linker_files);
 1201         else {
 1202                 lf = linker_find_file_by_id(uap->fileid);
 1203                 if (lf == NULL) {
 1204                         error = ENOENT;
 1205                         goto out;
 1206                 }
 1207                 lf = TAILQ_NEXT(lf, link);
 1208         }
 1209 
 1210         /* Skip partially loaded files. */
 1211         while (lf != NULL && !(lf->flags & LINKER_FILE_LINKED))
 1212                 lf = TAILQ_NEXT(lf, link);
 1213 
 1214         if (lf)
 1215                 td->td_retval[0] = lf->id;
 1216         else
 1217                 td->td_retval[0] = 0;
 1218 out:
 1219         sx_xunlock(&kld_sx);
 1220         return (error);
 1221 }
 1222 
 1223 int
 1224 sys_kldstat(struct thread *td, struct kldstat_args *uap)
 1225 {
 1226         struct kld_file_stat *stat;
 1227         int error, version;
 1228 
 1229         /*
 1230          * Check the version of the user's structure.
 1231          */
 1232         if ((error = copyin(&uap->stat->version, &version, sizeof(version)))
 1233             != 0)
 1234                 return (error);
 1235         if (version != sizeof(struct kld_file_stat_1) &&
 1236             version != sizeof(struct kld_file_stat))
 1237                 return (EINVAL);
 1238 
 1239         stat = malloc(sizeof(*stat), M_TEMP, M_WAITOK | M_ZERO);
 1240         error = kern_kldstat(td, uap->fileid, stat);
 1241         if (error == 0)
 1242                 error = copyout(stat, uap->stat, version);
 1243         free(stat, M_TEMP);
 1244         return (error);
 1245 }
 1246 
 1247 int
 1248 kern_kldstat(struct thread *td, int fileid, struct kld_file_stat *stat)
 1249 {
 1250         linker_file_t lf;
 1251         int namelen;
 1252 #ifdef MAC
 1253         int error;
 1254 
 1255         error = mac_kld_check_stat(td->td_ucred);
 1256         if (error)
 1257                 return (error);
 1258 #endif
 1259 
 1260         sx_xlock(&kld_sx);
 1261         lf = linker_find_file_by_id(fileid);
 1262         if (lf == NULL) {
 1263                 sx_xunlock(&kld_sx);
 1264                 return (ENOENT);
 1265         }
 1266 
 1267         /* Version 1 fields: */
 1268         namelen = strlen(lf->filename) + 1;
 1269         if (namelen > MAXPATHLEN)
 1270                 namelen = MAXPATHLEN;
 1271         bcopy(lf->filename, &stat->name[0], namelen);
 1272         stat->refs = lf->refs;
 1273         stat->id = lf->id;
 1274         stat->address = lf->address;
 1275         stat->size = lf->size;
 1276         /* Version 2 fields: */
 1277         namelen = strlen(lf->pathname) + 1;
 1278         if (namelen > MAXPATHLEN)
 1279                 namelen = MAXPATHLEN;
 1280         bcopy(lf->pathname, &stat->pathname[0], namelen);
 1281         sx_xunlock(&kld_sx);
 1282 
 1283         td->td_retval[0] = 0;
 1284         return (0);
 1285 }
 1286 
 1287 int
 1288 sys_kldfirstmod(struct thread *td, struct kldfirstmod_args *uap)
 1289 {
 1290         linker_file_t lf;
 1291         module_t mp;
 1292         int error = 0;
 1293 
 1294 #ifdef MAC
 1295         error = mac_kld_check_stat(td->td_ucred);
 1296         if (error)
 1297                 return (error);
 1298 #endif
 1299 
 1300         sx_xlock(&kld_sx);
 1301         lf = linker_find_file_by_id(uap->fileid);
 1302         if (lf) {
 1303                 MOD_SLOCK;
 1304                 mp = TAILQ_FIRST(&lf->modules);
 1305                 if (mp != NULL)
 1306                         td->td_retval[0] = module_getid(mp);
 1307                 else
 1308                         td->td_retval[0] = 0;
 1309                 MOD_SUNLOCK;
 1310         } else
 1311                 error = ENOENT;
 1312         sx_xunlock(&kld_sx);
 1313         return (error);
 1314 }
 1315 
 1316 int
 1317 sys_kldsym(struct thread *td, struct kldsym_args *uap)
 1318 {
 1319         char *symstr = NULL;
 1320         c_linker_sym_t sym;
 1321         linker_symval_t symval;
 1322         linker_file_t lf;
 1323         struct kld_sym_lookup lookup;
 1324         int error = 0;
 1325 
 1326 #ifdef MAC
 1327         error = mac_kld_check_stat(td->td_ucred);
 1328         if (error)
 1329                 return (error);
 1330 #endif
 1331 
 1332         if ((error = copyin(uap->data, &lookup, sizeof(lookup))) != 0)
 1333                 return (error);
 1334         if (lookup.version != sizeof(lookup) ||
 1335             uap->cmd != KLDSYM_LOOKUP)
 1336                 return (EINVAL);
 1337         symstr = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
 1338         if ((error = copyinstr(lookup.symname, symstr, MAXPATHLEN, NULL)) != 0)
 1339                 goto out;
 1340         sx_xlock(&kld_sx);
 1341         if (uap->fileid != 0) {
 1342                 lf = linker_find_file_by_id(uap->fileid);
 1343                 if (lf == NULL)
 1344                         error = ENOENT;
 1345                 else if (LINKER_LOOKUP_SYMBOL(lf, symstr, &sym) == 0 &&
 1346                     LINKER_SYMBOL_VALUES(lf, sym, &symval) == 0) {
 1347                         lookup.symvalue = (uintptr_t) symval.value;
 1348                         lookup.symsize = symval.size;
 1349                         error = copyout(&lookup, uap->data, sizeof(lookup));
 1350                 } else
 1351                         error = ENOENT;
 1352         } else {
 1353                 TAILQ_FOREACH(lf, &linker_files, link) {
 1354                         if (LINKER_LOOKUP_SYMBOL(lf, symstr, &sym) == 0 &&
 1355                             LINKER_SYMBOL_VALUES(lf, sym, &symval) == 0) {
 1356                                 lookup.symvalue = (uintptr_t)symval.value;
 1357                                 lookup.symsize = symval.size;
 1358                                 error = copyout(&lookup, uap->data,
 1359                                     sizeof(lookup));
 1360                                 break;
 1361                         }
 1362                 }
 1363                 if (lf == NULL)
 1364                         error = ENOENT;
 1365         }
 1366         sx_xunlock(&kld_sx);
 1367 out:
 1368         free(symstr, M_TEMP);
 1369         return (error);
 1370 }
 1371 
 1372 /*
 1373  * Preloaded module support
 1374  */
 1375 
 1376 static modlist_t
 1377 modlist_lookup(const char *name, int ver)
 1378 {
 1379         modlist_t mod;
 1380 
 1381         TAILQ_FOREACH(mod, &found_modules, link) {
 1382                 if (strcmp(mod->name, name) == 0 &&
 1383                     (ver == 0 || mod->version == ver))
 1384                         return (mod);
 1385         }
 1386         return (NULL);
 1387 }
 1388 
 1389 static modlist_t
 1390 modlist_lookup2(const char *name, struct mod_depend *verinfo)
 1391 {
 1392         modlist_t mod, bestmod;
 1393         int ver;
 1394 
 1395         if (verinfo == NULL)
 1396                 return (modlist_lookup(name, 0));
 1397         bestmod = NULL;
 1398         TAILQ_FOREACH(mod, &found_modules, link) {
 1399                 if (strcmp(mod->name, name) != 0)
 1400                         continue;
 1401                 ver = mod->version;
 1402                 if (ver == verinfo->md_ver_preferred)
 1403                         return (mod);
 1404                 if (ver >= verinfo->md_ver_minimum &&
 1405                     ver <= verinfo->md_ver_maximum &&
 1406                     (bestmod == NULL || ver > bestmod->version))
 1407                         bestmod = mod;
 1408         }
 1409         return (bestmod);
 1410 }
 1411 
 1412 static modlist_t
 1413 modlist_newmodule(const char *modname, int version, linker_file_t container)
 1414 {
 1415         modlist_t mod;
 1416 
 1417         mod = malloc(sizeof(struct modlist), M_LINKER, M_NOWAIT | M_ZERO);
 1418         if (mod == NULL)
 1419                 panic("no memory for module list");
 1420         mod->container = container;
 1421         mod->name = modname;
 1422         mod->version = version;
 1423         TAILQ_INSERT_TAIL(&found_modules, mod, link);
 1424         return (mod);
 1425 }
 1426 
 1427 static void
 1428 linker_addmodules(linker_file_t lf, struct mod_metadata **start,
 1429     struct mod_metadata **stop, int preload)
 1430 {
 1431         struct mod_metadata *mp, **mdp;
 1432         const char *modname;
 1433         int ver;
 1434 
 1435         for (mdp = start; mdp < stop; mdp++) {
 1436                 mp = *mdp;
 1437                 if (mp->md_type != MDT_VERSION)
 1438                         continue;
 1439                 modname = mp->md_cval;
 1440                 ver = ((struct mod_version *)mp->md_data)->mv_version;
 1441                 if (modlist_lookup(modname, ver) != NULL) {
 1442                         printf("module %s already present!\n", modname);
 1443                         /* XXX what can we do? this is a build error. :-( */
 1444                         continue;
 1445                 }
 1446                 modlist_newmodule(modname, ver, lf);
 1447         }
 1448 }
 1449 
 1450 static void
 1451 linker_preload(void *arg)
 1452 {
 1453         caddr_t modptr;
 1454         const char *modname, *nmodname;
 1455         char *modtype;
 1456         linker_file_t lf, nlf;
 1457         linker_class_t lc;
 1458         int error;
 1459         linker_file_list_t loaded_files;
 1460         linker_file_list_t depended_files;
 1461         struct mod_metadata *mp, *nmp;
 1462         struct mod_metadata **start, **stop, **mdp, **nmdp;
 1463         struct mod_depend *verinfo;
 1464         int nver;
 1465         int resolves;
 1466         modlist_t mod;
 1467         struct sysinit **si_start, **si_stop;
 1468 
 1469         TAILQ_INIT(&loaded_files);
 1470         TAILQ_INIT(&depended_files);
 1471         TAILQ_INIT(&found_modules);
 1472         error = 0;
 1473 
 1474         modptr = NULL;
 1475         sx_xlock(&kld_sx);
 1476         while ((modptr = preload_search_next_name(modptr)) != NULL) {
 1477                 modname = (char *)preload_search_info(modptr, MODINFO_NAME);
 1478                 modtype = (char *)preload_search_info(modptr, MODINFO_TYPE);
 1479                 if (modname == NULL) {
 1480                         printf("Preloaded module at %p does not have a"
 1481                             " name!\n", modptr);
 1482                         continue;
 1483                 }
 1484                 if (modtype == NULL) {
 1485                         printf("Preloaded module at %p does not have a type!\n",
 1486                             modptr);
 1487                         continue;
 1488                 }
 1489                 if (bootverbose)
 1490                         printf("Preloaded %s \"%s\" at %p.\n", modtype, modname,
 1491                             modptr);
 1492                 lf = NULL;
 1493                 TAILQ_FOREACH(lc, &classes, link) {
 1494                         error = LINKER_LINK_PRELOAD(lc, modname, &lf);
 1495                         if (!error)
 1496                                 break;
 1497                         lf = NULL;
 1498                 }
 1499                 if (lf)
 1500                         TAILQ_INSERT_TAIL(&loaded_files, lf, loaded);
 1501         }
 1502 
 1503         /*
 1504          * First get a list of stuff in the kernel.
 1505          */
 1506         if (linker_file_lookup_set(linker_kernel_file, MDT_SETNAME, &start,
 1507             &stop, NULL) == 0)
 1508                 linker_addmodules(linker_kernel_file, start, stop, 1);
 1509 
 1510         /*
 1511          * This is a once-off kinky bubble sort to resolve relocation
 1512          * dependency requirements.
 1513          */
 1514 restart:
 1515         TAILQ_FOREACH(lf, &loaded_files, loaded) {
 1516                 error = linker_file_lookup_set(lf, MDT_SETNAME, &start,
 1517                     &stop, NULL);
 1518                 /*
 1519                  * First, look to see if we would successfully link with this
 1520                  * stuff.
 1521                  */
 1522                 resolves = 1;   /* unless we know otherwise */
 1523                 if (!error) {
 1524                         for (mdp = start; mdp < stop; mdp++) {
 1525                                 mp = *mdp;
 1526                                 if (mp->md_type != MDT_DEPEND)
 1527                                         continue;
 1528                                 modname = mp->md_cval;
 1529                                 verinfo = mp->md_data;
 1530                                 for (nmdp = start; nmdp < stop; nmdp++) {
 1531                                         nmp = *nmdp;
 1532                                         if (nmp->md_type != MDT_VERSION)
 1533                                                 continue;
 1534                                         nmodname = nmp->md_cval;
 1535                                         if (strcmp(modname, nmodname) == 0)
 1536                                                 break;
 1537                                 }
 1538                                 if (nmdp < stop)   /* it's a self reference */
 1539                                         continue;
 1540 
 1541                                 /*
 1542                                  * ok, the module isn't here yet, we
 1543                                  * are not finished
 1544                                  */
 1545                                 if (modlist_lookup2(modname, verinfo) == NULL)
 1546                                         resolves = 0;
 1547                         }
 1548                 }
 1549                 /*
 1550                  * OK, if we found our modules, we can link.  So, "provide"
 1551                  * the modules inside and add it to the end of the link order
 1552                  * list.
 1553                  */
 1554                 if (resolves) {
 1555                         if (!error) {
 1556                                 for (mdp = start; mdp < stop; mdp++) {
 1557                                         mp = *mdp;
 1558                                         if (mp->md_type != MDT_VERSION)
 1559                                                 continue;
 1560                                         modname = mp->md_cval;
 1561                                         nver = ((struct mod_version *)
 1562                                             mp->md_data)->mv_version;
 1563                                         if (modlist_lookup(modname,
 1564                                             nver) != NULL) {
 1565                                                 printf("module %s already"
 1566                                                     " present!\n", modname);
 1567                                                 TAILQ_REMOVE(&loaded_files,
 1568                                                     lf, loaded);
 1569                                                 linker_file_unload(lf,
 1570                                                     LINKER_UNLOAD_FORCE);
 1571                                                 /* we changed tailq next ptr */
 1572                                                 goto restart;
 1573                                         }
 1574                                         modlist_newmodule(modname, nver, lf);
 1575                                 }
 1576                         }
 1577                         TAILQ_REMOVE(&loaded_files, lf, loaded);
 1578                         TAILQ_INSERT_TAIL(&depended_files, lf, loaded);
 1579                         /*
 1580                          * Since we provided modules, we need to restart the
 1581                          * sort so that the previous files that depend on us
 1582                          * have a chance. Also, we've busted the tailq next
 1583                          * pointer with the REMOVE.
 1584                          */
 1585                         goto restart;
 1586                 }
 1587         }
 1588 
 1589         /*
 1590          * At this point, we check to see what could not be resolved..
 1591          */
 1592         while ((lf = TAILQ_FIRST(&loaded_files)) != NULL) {
 1593                 TAILQ_REMOVE(&loaded_files, lf, loaded);
 1594                 printf("KLD file %s is missing dependencies\n", lf->filename);
 1595                 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
 1596         }
 1597 
 1598         /*
 1599          * We made it. Finish off the linking in the order we determined.
 1600          */
 1601         TAILQ_FOREACH_SAFE(lf, &depended_files, loaded, nlf) {
 1602                 if (linker_kernel_file) {
 1603                         linker_kernel_file->refs++;
 1604                         error = linker_file_add_dependency(lf,
 1605                             linker_kernel_file);
 1606                         if (error)
 1607                                 panic("cannot add dependency");
 1608                 }
 1609                 lf->userrefs++; /* so we can (try to) kldunload it */
 1610                 error = linker_file_lookup_set(lf, MDT_SETNAME, &start,
 1611                     &stop, NULL);
 1612                 if (!error) {
 1613                         for (mdp = start; mdp < stop; mdp++) {
 1614                                 mp = *mdp;
 1615                                 if (mp->md_type != MDT_DEPEND)
 1616                                         continue;
 1617                                 modname = mp->md_cval;
 1618                                 verinfo = mp->md_data;
 1619                                 mod = modlist_lookup2(modname, verinfo);
 1620                                 if (mod == NULL) {
 1621                                         printf("KLD file %s - cannot find "
 1622                                             "dependency \"%s\"\n",
 1623                                             lf->filename, modname);
 1624                                         goto fail;
 1625                                 }
 1626                                 /* Don't count self-dependencies */
 1627                                 if (lf == mod->container)
 1628                                         continue;
 1629                                 mod->container->refs++;
 1630                                 error = linker_file_add_dependency(lf,
 1631                                     mod->container);
 1632                                 if (error)
 1633                                         panic("cannot add dependency");
 1634                         }
 1635                 }
 1636                 /*
 1637                  * Now do relocation etc using the symbol search paths
 1638                  * established by the dependencies
 1639                  */
 1640                 error = LINKER_LINK_PRELOAD_FINISH(lf);
 1641                 if (error) {
 1642                         printf("KLD file %s - could not finalize loading\n",
 1643                             lf->filename);
 1644                         goto fail;
 1645                 }
 1646                 linker_file_register_modules(lf);
 1647                 if (linker_file_lookup_set(lf, "sysinit_set", &si_start,
 1648                     &si_stop, NULL) == 0)
 1649                         sysinit_add(si_start, si_stop);
 1650                 linker_file_register_sysctls(lf, true);
 1651                 lf->flags |= LINKER_FILE_LINKED;
 1652                 continue;
 1653 fail:
 1654                 TAILQ_REMOVE(&depended_files, lf, loaded);
 1655                 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
 1656         }
 1657         sx_xunlock(&kld_sx);
 1658         /* woohoo! we made it! */
 1659 }
 1660 
 1661 SYSINIT(preload, SI_SUB_KLD, SI_ORDER_MIDDLE, linker_preload, 0);
 1662 
 1663 /*
 1664  * Search for a not-loaded module by name.
 1665  *
 1666  * Modules may be found in the following locations:
 1667  *
 1668  * - preloaded (result is just the module name) - on disk (result is full path
 1669  * to module)
 1670  *
 1671  * If the module name is qualified in any way (contains path, etc.) the we
 1672  * simply return a copy of it.
 1673  *
 1674  * The search path can be manipulated via sysctl.  Note that we use the ';'
 1675  * character as a separator to be consistent with the bootloader.
 1676  */
 1677 
 1678 static char linker_hintfile[] = "linker.hints";
 1679 static char linker_path[MAXPATHLEN] = "/boot/kernel;/boot/modules";
 1680 
 1681 SYSCTL_STRING(_kern, OID_AUTO, module_path, CTLFLAG_RW, linker_path,
 1682     sizeof(linker_path), "module load search path");
 1683 
 1684 TUNABLE_STR("module_path", linker_path, sizeof(linker_path));
 1685 
 1686 static char *linker_ext_list[] = {
 1687         "",
 1688         ".ko",
 1689         NULL
 1690 };
 1691 
 1692 /*
 1693  * Check if file actually exists either with or without extension listed in
 1694  * the linker_ext_list. (probably should be generic for the rest of the
 1695  * kernel)
 1696  */
 1697 static char *
 1698 linker_lookup_file(const char *path, int pathlen, const char *name,
 1699     int namelen, struct vattr *vap)
 1700 {
 1701         struct nameidata nd;
 1702         struct thread *td = curthread;  /* XXX */
 1703         char *result, **cpp, *sep;
 1704         int error, len, extlen, reclen, flags;
 1705         enum vtype type;
 1706 
 1707         extlen = 0;
 1708         for (cpp = linker_ext_list; *cpp; cpp++) {
 1709                 len = strlen(*cpp);
 1710                 if (len > extlen)
 1711                         extlen = len;
 1712         }
 1713         extlen++;               /* trailing '\0' */
 1714         sep = (path[pathlen - 1] != '/') ? "/" : "";
 1715 
 1716         reclen = pathlen + strlen(sep) + namelen + extlen + 1;
 1717         result = malloc(reclen, M_LINKER, M_WAITOK);
 1718         for (cpp = linker_ext_list; *cpp; cpp++) {
 1719                 snprintf(result, reclen, "%.*s%s%.*s%s", pathlen, path, sep,
 1720                     namelen, name, *cpp);
 1721                 /*
 1722                  * Attempt to open the file, and return the path if
 1723                  * we succeed and it's a regular file.
 1724                  */
 1725                 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, result, td);
 1726                 flags = FREAD;
 1727                 error = vn_open(&nd, &flags, 0, NULL);
 1728                 if (error == 0) {
 1729                         NDFREE(&nd, NDF_ONLY_PNBUF);
 1730                         type = nd.ni_vp->v_type;
 1731                         if (vap)
 1732                                 VOP_GETATTR(nd.ni_vp, vap, td->td_ucred);
 1733                         VOP_UNLOCK(nd.ni_vp, 0);
 1734                         vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
 1735                         if (type == VREG)
 1736                                 return (result);
 1737                 }
 1738         }
 1739         free(result, M_LINKER);
 1740         return (NULL);
 1741 }
 1742 
 1743 #define INT_ALIGN(base, ptr)    ptr =                                   \
 1744         (base) + (((ptr) - (base) + sizeof(int) - 1) & ~(sizeof(int) - 1))
 1745 
 1746 /*
 1747  * Lookup KLD which contains requested module in the "linker.hints" file. If
 1748  * version specification is available, then try to find the best KLD.
 1749  * Otherwise just find the latest one.
 1750  */
 1751 static char *
 1752 linker_hints_lookup(const char *path, int pathlen, const char *modname,
 1753     int modnamelen, struct mod_depend *verinfo)
 1754 {
 1755         struct thread *td = curthread;  /* XXX */
 1756         struct ucred *cred = td ? td->td_ucred : NULL;
 1757         struct nameidata nd;
 1758         struct vattr vattr, mattr;
 1759         u_char *hints = NULL;
 1760         u_char *cp, *recptr, *bufend, *result, *best, *pathbuf, *sep;
 1761         int error, ival, bestver, *intp, found, flags, clen, blen;
 1762         ssize_t reclen;
 1763 
 1764         result = NULL;
 1765         bestver = found = 0;
 1766 
 1767         sep = (path[pathlen - 1] != '/') ? "/" : "";
 1768         reclen = imax(modnamelen, strlen(linker_hintfile)) + pathlen +
 1769             strlen(sep) + 1;
 1770         pathbuf = malloc(reclen, M_LINKER, M_WAITOK);
 1771         snprintf(pathbuf, reclen, "%.*s%s%s", pathlen, path, sep,
 1772             linker_hintfile);
 1773 
 1774         NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, pathbuf, td);
 1775         flags = FREAD;
 1776         error = vn_open(&nd, &flags, 0, NULL);
 1777         if (error)
 1778                 goto bad;
 1779         NDFREE(&nd, NDF_ONLY_PNBUF);
 1780         if (nd.ni_vp->v_type != VREG)
 1781                 goto bad;
 1782         best = cp = NULL;
 1783         error = VOP_GETATTR(nd.ni_vp, &vattr, cred);
 1784         if (error)
 1785                 goto bad;
 1786         /*
 1787          * XXX: we need to limit this number to some reasonable value
 1788          */
 1789         if (vattr.va_size > 100 * 1024) {
 1790                 printf("hints file too large %ld\n", (long)vattr.va_size);
 1791                 goto bad;
 1792         }
 1793         hints = malloc(vattr.va_size, M_TEMP, M_WAITOK);
 1794         error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)hints, vattr.va_size, 0,
 1795             UIO_SYSSPACE, IO_NODELOCKED, cred, NOCRED, &reclen, td);
 1796         if (error)
 1797                 goto bad;
 1798         VOP_UNLOCK(nd.ni_vp, 0);
 1799         vn_close(nd.ni_vp, FREAD, cred, td);
 1800         nd.ni_vp = NULL;
 1801         if (reclen != 0) {
 1802                 printf("can't read %zd\n", reclen);
 1803                 goto bad;
 1804         }
 1805         intp = (int *)hints;
 1806         ival = *intp++;
 1807         if (ival != LINKER_HINTS_VERSION) {
 1808                 printf("hints file version mismatch %d\n", ival);
 1809                 goto bad;
 1810         }
 1811         bufend = hints + vattr.va_size;
 1812         recptr = (u_char *)intp;
 1813         clen = blen = 0;
 1814         while (recptr < bufend && !found) {
 1815                 intp = (int *)recptr;
 1816                 reclen = *intp++;
 1817                 ival = *intp++;
 1818                 cp = (char *)intp;
 1819                 switch (ival) {
 1820                 case MDT_VERSION:
 1821                         clen = *cp++;
 1822                         if (clen != modnamelen || bcmp(cp, modname, clen) != 0)
 1823                                 break;
 1824                         cp += clen;
 1825                         INT_ALIGN(hints, cp);
 1826                         ival = *(int *)cp;
 1827                         cp += sizeof(int);
 1828                         clen = *cp++;
 1829                         if (verinfo == NULL ||
 1830                             ival == verinfo->md_ver_preferred) {
 1831                                 found = 1;
 1832                                 break;
 1833                         }
 1834                         if (ival >= verinfo->md_ver_minimum &&
 1835                             ival <= verinfo->md_ver_maximum &&
 1836                             ival > bestver) {
 1837                                 bestver = ival;
 1838                                 best = cp;
 1839                                 blen = clen;
 1840                         }
 1841                         break;
 1842                 default:
 1843                         break;
 1844                 }
 1845                 recptr += reclen + sizeof(int);
 1846         }
 1847         /*
 1848          * Finally check if KLD is in the place
 1849          */
 1850         if (found)
 1851                 result = linker_lookup_file(path, pathlen, cp, clen, &mattr);
 1852         else if (best)
 1853                 result = linker_lookup_file(path, pathlen, best, blen, &mattr);
 1854 
 1855         /*
 1856          * KLD is newer than hints file. What we should do now?
 1857          */
 1858         if (result && timespeccmp(&mattr.va_mtime, &vattr.va_mtime, >))
 1859                 printf("warning: KLD '%s' is newer than the linker.hints"
 1860                     " file\n", result);
 1861 bad:
 1862         free(pathbuf, M_LINKER);
 1863         if (hints)
 1864                 free(hints, M_TEMP);
 1865         if (nd.ni_vp != NULL) {
 1866                 VOP_UNLOCK(nd.ni_vp, 0);
 1867                 vn_close(nd.ni_vp, FREAD, cred, td);
 1868         }
 1869         /*
 1870          * If nothing found or hints is absent - fallback to the old
 1871          * way by using "kldname[.ko]" as module name.
 1872          */
 1873         if (!found && !bestver && result == NULL)
 1874                 result = linker_lookup_file(path, pathlen, modname,
 1875                     modnamelen, NULL);
 1876         return (result);
 1877 }
 1878 
 1879 /*
 1880  * Lookup KLD which contains requested module in the all directories.
 1881  */
 1882 static char *
 1883 linker_search_module(const char *modname, int modnamelen,
 1884     struct mod_depend *verinfo)
 1885 {
 1886         char *cp, *ep, *result;
 1887 
 1888         /*
 1889          * traverse the linker path
 1890          */
 1891         for (cp = linker_path; *cp; cp = ep + 1) {
 1892                 /* find the end of this component */
 1893                 for (ep = cp; (*ep != 0) && (*ep != ';'); ep++);
 1894                 result = linker_hints_lookup(cp, ep - cp, modname,
 1895                     modnamelen, verinfo);
 1896                 if (result != NULL)
 1897                         return (result);
 1898                 if (*ep == 0)
 1899                         break;
 1900         }
 1901         return (NULL);
 1902 }
 1903 
 1904 /*
 1905  * Search for module in all directories listed in the linker_path.
 1906  */
 1907 static char *
 1908 linker_search_kld(const char *name)
 1909 {
 1910         char *cp, *ep, *result;
 1911         int len;
 1912 
 1913         /* qualified at all? */
 1914         if (strchr(name, '/'))
 1915                 return (strdup(name, M_LINKER));
 1916 
 1917         /* traverse the linker path */
 1918         len = strlen(name);
 1919         for (ep = linker_path; *ep; ep++) {
 1920                 cp = ep;
 1921                 /* find the end of this component */
 1922                 for (; *ep != 0 && *ep != ';'; ep++);
 1923                 result = linker_lookup_file(cp, ep - cp, name, len, NULL);
 1924                 if (result != NULL)
 1925                         return (result);
 1926         }
 1927         return (NULL);
 1928 }
 1929 
 1930 static const char *
 1931 linker_basename(const char *path)
 1932 {
 1933         const char *filename;
 1934 
 1935         filename = strrchr(path, '/');
 1936         if (filename == NULL)
 1937                 return path;
 1938         if (filename[1])
 1939                 filename++;
 1940         return (filename);
 1941 }
 1942 
 1943 #ifdef HWPMC_HOOKS
 1944 /*
 1945  * Inform hwpmc about the set of kernel modules currently loaded.
 1946  */
 1947 void *
 1948 linker_hwpmc_list_objects(void)
 1949 {
 1950         linker_file_t lf;
 1951         struct pmckern_map_in *kobase;
 1952         int i, nmappings;
 1953 
 1954         nmappings = 0;
 1955         sx_slock(&kld_sx);
 1956         TAILQ_FOREACH(lf, &linker_files, link)
 1957                 nmappings++;
 1958 
 1959         /* Allocate nmappings + 1 entries. */
 1960         kobase = malloc((nmappings + 1) * sizeof(struct pmckern_map_in),
 1961             M_LINKER, M_WAITOK | M_ZERO);
 1962         i = 0;
 1963         TAILQ_FOREACH(lf, &linker_files, link) {
 1964 
 1965                 /* Save the info for this linker file. */
 1966                 kobase[i].pm_file = lf->filename;
 1967                 kobase[i].pm_address = (uintptr_t)lf->address;
 1968                 i++;
 1969         }
 1970         sx_sunlock(&kld_sx);
 1971 
 1972         KASSERT(i > 0, ("linker_hpwmc_list_objects: no kernel objects?"));
 1973 
 1974         /* The last entry of the malloced area comprises of all zeros. */
 1975         KASSERT(kobase[i].pm_file == NULL,
 1976             ("linker_hwpmc_list_objects: last object not NULL"));
 1977 
 1978         return ((void *)kobase);
 1979 }
 1980 #endif
 1981 
 1982 /*
 1983  * Find a file which contains given module and load it, if "parent" is not
 1984  * NULL, register a reference to it.
 1985  */
 1986 static int
 1987 linker_load_module(const char *kldname, const char *modname,
 1988     struct linker_file *parent, struct mod_depend *verinfo,
 1989     struct linker_file **lfpp)
 1990 {
 1991         linker_file_t lfdep;
 1992         const char *filename;
 1993         char *pathname;
 1994         int error;
 1995 
 1996         sx_assert(&kld_sx, SA_XLOCKED);
 1997         if (modname == NULL) {
 1998                 /*
 1999                  * We have to load KLD
 2000                  */
 2001                 KASSERT(verinfo == NULL, ("linker_load_module: verinfo"
 2002                     " is not NULL"));
 2003                 pathname = linker_search_kld(kldname);
 2004         } else {
 2005                 if (modlist_lookup2(modname, verinfo) != NULL)
 2006                         return (EEXIST);
 2007                 if (kldname != NULL)
 2008                         pathname = strdup(kldname, M_LINKER);
 2009                 else if (rootvnode == NULL)
 2010                         pathname = NULL;
 2011                 else
 2012                         /*
 2013                          * Need to find a KLD with required module
 2014                          */
 2015                         pathname = linker_search_module(modname,
 2016                             strlen(modname), verinfo);
 2017         }
 2018         if (pathname == NULL)
 2019                 return (ENOENT);
 2020 
 2021         /*
 2022          * Can't load more than one file with the same basename XXX:
 2023          * Actually it should be possible to have multiple KLDs with
 2024          * the same basename but different path because they can
 2025          * provide different versions of the same modules.
 2026          */
 2027         filename = linker_basename(pathname);
 2028         if (linker_find_file_by_name(filename))
 2029                 error = EEXIST;
 2030         else do {
 2031                 error = linker_load_file(pathname, &lfdep);
 2032                 if (error)
 2033                         break;
 2034                 if (modname && verinfo &&
 2035                     modlist_lookup2(modname, verinfo) == NULL) {
 2036                         linker_file_unload(lfdep, LINKER_UNLOAD_FORCE);
 2037                         error = ENOENT;
 2038                         break;
 2039                 }
 2040                 if (parent) {
 2041                         error = linker_file_add_dependency(parent, lfdep);
 2042                         if (error)
 2043                                 break;
 2044                 }
 2045                 if (lfpp)
 2046                         *lfpp = lfdep;
 2047         } while (0);
 2048         free(pathname, M_LINKER);
 2049         return (error);
 2050 }
 2051 
 2052 /*
 2053  * This routine is responsible for finding dependencies of userland initiated
 2054  * kldload(2)'s of files.
 2055  */
 2056 int
 2057 linker_load_dependencies(linker_file_t lf)
 2058 {
 2059         linker_file_t lfdep;
 2060         struct mod_metadata **start, **stop, **mdp, **nmdp;
 2061         struct mod_metadata *mp, *nmp;
 2062         struct mod_depend *verinfo;
 2063         modlist_t mod;
 2064         const char *modname, *nmodname;
 2065         int ver, error = 0, count;
 2066 
 2067         /*
 2068          * All files are dependent on /kernel.
 2069          */
 2070         sx_assert(&kld_sx, SA_XLOCKED);
 2071         if (linker_kernel_file) {
 2072                 linker_kernel_file->refs++;
 2073                 error = linker_file_add_dependency(lf, linker_kernel_file);
 2074                 if (error)
 2075                         return (error);
 2076         }
 2077         if (linker_file_lookup_set(lf, MDT_SETNAME, &start, &stop,
 2078             &count) != 0)
 2079                 return (0);
 2080         for (mdp = start; mdp < stop; mdp++) {
 2081                 mp = *mdp;
 2082                 if (mp->md_type != MDT_VERSION)
 2083                         continue;
 2084                 modname = mp->md_cval;
 2085                 ver = ((struct mod_version *)mp->md_data)->mv_version;
 2086                 mod = modlist_lookup(modname, ver);
 2087                 if (mod != NULL) {
 2088                         printf("interface %s.%d already present in the KLD"
 2089                             " '%s'!\n", modname, ver,
 2090                             mod->container->filename);
 2091                         return (EEXIST);
 2092                 }
 2093         }
 2094 
 2095         for (mdp = start; mdp < stop; mdp++) {
 2096                 mp = *mdp;
 2097                 if (mp->md_type != MDT_DEPEND)
 2098                         continue;
 2099                 modname = mp->md_cval;
 2100                 verinfo = mp->md_data;
 2101                 nmodname = NULL;
 2102                 for (nmdp = start; nmdp < stop; nmdp++) {
 2103                         nmp = *nmdp;
 2104                         if (nmp->md_type != MDT_VERSION)
 2105                                 continue;
 2106                         nmodname = nmp->md_cval;
 2107                         if (strcmp(modname, nmodname) == 0)
 2108                                 break;
 2109                 }
 2110                 if (nmdp < stop)/* early exit, it's a self reference */
 2111                         continue;
 2112                 mod = modlist_lookup2(modname, verinfo);
 2113                 if (mod) {      /* woohoo, it's loaded already */
 2114                         lfdep = mod->container;
 2115                         lfdep->refs++;
 2116                         error = linker_file_add_dependency(lf, lfdep);
 2117                         if (error)
 2118                                 break;
 2119                         continue;
 2120                 }
 2121                 error = linker_load_module(NULL, modname, lf, verinfo, NULL);
 2122                 if (error) {
 2123                         printf("KLD %s: depends on %s - not available or"
 2124                             " version mismatch\n", lf->filename, modname);
 2125                         break;
 2126                 }
 2127         }
 2128 
 2129         if (error)
 2130                 return (error);
 2131         linker_addmodules(lf, start, stop, 0);
 2132         return (error);
 2133 }
 2134 
 2135 static int
 2136 sysctl_kern_function_list_iterate(const char *name, void *opaque)
 2137 {
 2138         struct sysctl_req *req;
 2139 
 2140         req = opaque;
 2141         return (SYSCTL_OUT(req, name, strlen(name) + 1));
 2142 }
 2143 
 2144 /*
 2145  * Export a nul-separated, double-nul-terminated list of all function names
 2146  * in the kernel.
 2147  */
 2148 static int
 2149 sysctl_kern_function_list(SYSCTL_HANDLER_ARGS)
 2150 {
 2151         linker_file_t lf;
 2152         int error;
 2153 
 2154 #ifdef MAC
 2155         error = mac_kld_check_stat(req->td->td_ucred);
 2156         if (error)
 2157                 return (error);
 2158 #endif
 2159         error = sysctl_wire_old_buffer(req, 0);
 2160         if (error != 0)
 2161                 return (error);
 2162         sx_xlock(&kld_sx);
 2163         TAILQ_FOREACH(lf, &linker_files, link) {
 2164                 error = LINKER_EACH_FUNCTION_NAME(lf,
 2165                     sysctl_kern_function_list_iterate, req);
 2166                 if (error) {
 2167                         sx_xunlock(&kld_sx);
 2168                         return (error);
 2169                 }
 2170         }
 2171         sx_xunlock(&kld_sx);
 2172         return (SYSCTL_OUT(req, "", 1));
 2173 }
 2174 
 2175 SYSCTL_PROC(_kern, OID_AUTO, function_list, CTLTYPE_OPAQUE | CTLFLAG_RD,
 2176     NULL, 0, sysctl_kern_function_list, "", "kernel function list");

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